Vacuum controlled dampening device for secondary throttles



T. F. CRAMER 2,990,823

VACUUM CONTROLLED DAMPENING DEVICE FOR SECONDARY THROTTLES July 4, 1961 2 Sheets-Sheet 1 Filed Dec. 8, 1958 3 on Ev w m v mm ow 7 mm 1 mb n l IEWU. om mm W E. n mm mm mm A l0 8. vmn mm. 02 m0. H mo. 5 A mm X. wo2 w: .vm 1 l I \wo \mo \u M O: /N: mm mm 09 mm ATTORN YS July 4, 1961 T, F. CRAMER 2,990,823

VACUUM CONTROLLED DAMPENING DEVICE FOR SECONDARY THROTTLES Filed Dec. 8, 1958 2 Sheets-Sheet 2 4 INVENTOR.

ATTORNEYS United States. Patent '6 2,990,823 VACUUM CONTROLLED DAMPENING DEVICE FOR SECONDARY THROTTLES Thomas F. Cramer, Warren, 'Mich., assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Dec. 8, 1958, Ser. No. 778,935 17 Claims. (Cl. 123-103) This invention pertains to a selective dampening device and more particularly to a dampening device for use with a secondary throttle plate in an internal combustion engine multiple stage carburetion system.

A multiple stage carburetion system comprises an operator-controlled primary throttle plate assembly and a venturi vacuum controlled secondary throttle plate assembly which is operable to supply additional fuel mixture flow to the combustion chambers at high speeds.

In engines having governing systems wherein at govcrned speed the primary throttle plate is automatically adjusted to restrict the fuel mixture flow to the combustion chambers, the subsequent movement of venturi-operated secondary plate is delayed and very quick, causing a compensating opening of the primary plate. The secondary plate in turn opens slightly due to the increased flow through the primary venturi and repeated alternate adjustments or hunting of the primary and secondary plates result. This invention successfully prevents hunting by applying a dampening or resisting movement to the secondary plate so that its initial closing after governing is modified and subsequent changing of the primary throttle plate is substantially eliminated. It is therefore an object of this invention to provide a dampening means for secondary throttle plate movement during the governing action which includes frictionally engaging the actuating arm for the secondary throttle plate. It is another object to provide an engine vacuum responsive member having a shaftway therethrough which encloses the secondary throttle plate actuating arm so thatmovement of the member in response to engine vacuum will restrict and dampen arm movement.

A further object is to provide a spring urged piston connected to a pivotable member having a transverse shaftway therethrough which encloses a secondary throttle plate arm; said piston being responsive to engine vacuum to move against said spring and cause said member to pivot until the walls of said shaftway bear against said arm restricting arm movement.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention,

- wherein:

, FIGURE 1 is a side elevational view with portions thereof in cross-section of a four-barrel carburetor provided with a governor embodying the invention.

FIGURE 2 is a side elevational view, with portions thereof in cross-section, taken on the plane of line 2--2, FIGURE 1 and looking in the direction of the arrows.

FIGURE 3 is a bottom plan view taken on the plane of line 3--3, FIGURE 1, and looking in the direction of the arrows.

, FIGURE 4 is a section taken at 4--4, FIGURE 3, and illustrates the dampening means of this invention. FIGURE 5 is a section taken at 5-5, FIGURE 4, illustrating the connection of the pivotable member to the carburetor body.

Referring now to FIGURE 1, a four-barrel carburetor '10, of the type referred to above and having an air intake 12, is sectioned to expose one of the primary barrels 14 and one of the secondary barrels 16. barrel 14 is provided with a restriction or venturi throat The primary 7 Patented July 4, 1961 18 and a conventionally operated throttle plate 20 mounted on the shaft 22 which extends through the other primary barrel in which is mounted a throttle plate identical to plate 20. The secondary barrel 16 is also provided with a venturi throat 24 and a throttle plate 26 mounted on the shaft 28 which extends through the other secondary barrel in which is mounted another secondary plate.

While a particular four-barrel carburetor is shown for purposes of illustration, it will be apparent that vthe invention is equally applicable to two-barrel or other multistage carburetors.

A vacuum device 30, commonly referred to as a governor diaphragm assembly, is mounted on the boss 32, extending from the carburetor throttle body 34. The assembly 30 includes a body 36 formed to provide recesses 38 and 40. The recess 40 is covered by means of a flexible diaphragm 42 which is secured to the body 36 by means of a cover member 44 formed to provide an air-tight chamber 46 of which the flexible diaphragm 42 forms a wall. The cover member may be secured by any suitable means such as screws 47.

As shown by FIGURES 1 and 2, the diaphragm 42 has secured to the center thereof in a conventional manner a rod 48 passing through passage 50 in the body 36 and having a laterally extending end 52 pivotally secured to the lever 54 which is rigidly secured to'the end 56 of the primary throttle shaft 22 extending into the chamber 38. The shaft 22 is mounted in'an anti-friction bearing 39, and a spring 41 is disposed between the bearing 39 and the steel and leather Washers 43 and 45 to provide a seal.

A tension spring 58 attached between the adjustable pin 60, mounted in one of the holes 62 in the body 36, and

the fixed pin 64, secured to the lever 54,.tends to hold the primary throttle plate 20 in the open position. An atmospherically vented cover plate 66 may be secured by screws 68 to housing 36, thereby protecting the mechanism within chamber 38.

The orifice 72 at the primary venturi throat 18 and the orifice 74 below the primary throttle plate 20 are connected by means of the passages 76 and 78 having fixed restrictions 80 and 82 respectively with the passage 84 in the body member 36 and the passage 86 in the cover member 44 which lead to the chamber 46. A passage 88 connecting with passage 84 terminates in an opening in the body 36 adapted to receive a threaded fitting 90.

Located at any desired position on the engine is a governor valve assembly 92 comprising a stationary housing 94 adapted to be mounted on the engine and containing a shaft 96 driven in any suitable manner in proportion to engine or vehicle speed. Mounted for rotation with the shaft 96 is a laterally extending sleeve 98 having a spring 100 mounted within the axial passage 102 in the sleeve by attachment at one end to the internally threaded member 104, which is keyed in passage 102.

.Spring 100 is adjustable axially of sleeve 98 by turning the adjustment screw 106 which is reached by removing the access screw 108. The other end of thespring 100 is secured to the governor Weight 110 movable axially within the chamber 112 against the spring 100 and having at the free end thereof a valve 114 adapted to close the orifice 116 when the weight 110 is forced outwardly due to the rotation of the shaft 96 and the sleeve 98 in accordance wi-th engine speed. The engine or vehicle speed at which the orifice 116 will be closed is dependent, of course, upon the adjustment of the spring 100. It is apparent, also, that some other governor valve structure may be employed.

A vacuum balancing air bleed is provided through assembly 92 to chamber 46 when orifice 116 is uncovered. Conduit 118 between the air intake 12 of the 3 carburetor and the housing 94 and conduit 122 between the housing 4 and the passage 88 in the body 36 are provided so that when the engine or vehicle is operating at a speed insufficient to close the orifice 116, engine vacuum will draw clean air through the conduit 118, into the housing 94, through the orifice 116 and into the chamber 112, through the passage 102 and the axial passage 120 in the shaft 96 and thence through the conduit 122 to the governor diaphragm assembly 30. When the engine reaches governed speed, the orifice 116 is closed and the air bleed through conduit 122 is cut ofi. When this occurs, vacuum in the chamber 46 urges the diaphragm 42 downwardly, as in FIGURE 2, against the spring 58 to close the primary throttle plates 20.

A secondary throttle diaphragm assembly 124 is mounted at the opposite side of the throttle body 34. This assembly comprises a body 126 having a recess 128 vented to the atmosphere through a plate 130 secured by screw 132 and'a recess 134 closed by a flexible diaphragm 136 which is secured to the body 126 by means of a cover 138 formed to provide oppositely disposed chambers 140 and 142 between which the flexible diaphragm 136 forms a movable wall. The chamber 142 contains a compression spring 144 positioned between the cover 138 and the arm 146, which is secured to the center of the diaphragm 136, so that the spring 144 urges the arm 146 upwardly to rotate the lever 148 secured rigidly to .the secondary throttle shaft 28 counterclockwise, as in FIGURE 4, and close the secondary throttle plates 26. A conduit 150 extending between the chamber 142 and the vacuum passages 152 and 154 opening to the primary and secondary venturi throats 18 and 24 enables primary and/or secondary venturi vacuum to evacuate the chamber 142 and displace the diaphragm 136 downwardly, as in FIGURE 1, against the spring 144 to open the secondary throttle 26. The rate of the spring 144 is selected so that the secondary throttle plate 26 will be open at any predetermined venturi vacuum.

The structure described above, or its equivalent, is well known in the art, and proper governing action depends upon the particular closing of the throttle plates and 26 when the engine or vehicle has reached a predetermined governing speed so as to diminish or cut off the flow of motive fluid to the engine. However, in the case of dual carburetion as described above, the automatic closing of the secondary throttle plates 26 lags behind that of the primary throttle plates 20. This causes hunting, since the primary throttle plates have to first close farther than would otherwise be required to compensate for the open secondary plates and then open when the secondary plates finally close.

In order to remedy this situation, apparatus as shown in FIGURES 3-5, is provided for frictionally dampening the movement of arm 146 to eliminate plate hunting. Cylinder 156 is fixed to the carburetor body and houses for reciprocating movement therein piston 157. Passage 158 in cylinder body 156 connects piston 157 with an engine vacuum source such as manifold vacuum or governor vacuum. Set screw 161 is threadedly engaged with an end of cylinder body 156 and adjusts spring 162 by moving seating plate 163 axially of spring compression. A member 168 has formed therein a transverse shaftway 169 for housing arm 146 and is pivotally supported to the carburetor body by pin 170 (FIGURE 5). Link 166 connects piston 157 to a post 171 attached to member 168, which is non-collinear with the pin 170.

During governing action, the increased vacuum in passage 158 will move piston 157 against Spring 162 and pivot member or cylinder 168 in a clockwise direction until the walls of transverse shaftway 169 bear against arm 146 to dampen and restrict its movement. This increase in vacuum occurs after the closing of the primary throttle but before the closing of the secondary throttle 4 so that surge of the secondary throttle is prevented and hunting is eliminated.

While manifold vacuum connection to passage 158 will provide adequate vacuum to move piston 157 in the desired manner to dampen the secondary plate movement, it has been found that supplying governor vacuum from line 122 results in a very desirable response movement of piston 157 since this vacuum is not as sensitive to slight changes in engine load and speed. Of course, other suitable actuating means for piston 157 may be used to properly and timely dampen the movement of arm 146.

If desired, of course, all or any part of the structure shown herein may be incorporated into a single, compact carburetor unit adapted for placement in a vehicle engine compartment.

The drawings and the foregoing specification constitute a description of the improved vacuum controlled dampening device for secondary throttles in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A dampening device for use in an internal combustion engine carburetor having a throttle plate pivotally mounted therein comprising actuating means for moving said throttle plate from an open to close position, friction means engageable with said actuating means to dampen the movement thereof, control means for engaging said friction means with and disengaging said friction means from said actuating means, said control means being responsive to a selected engine condition which is a function of speed to frictionally retard the movement of said actuating means.

2. A dampening device for use with the pivotally mounted secondary throttle plate of an internal combustion engine carburetor comprising actuating means for moving said throttle plate from an open to close position, friction means engageable with said actuating means to dampen the movement thereof, control means for engaging said friction means with and disengaging said friction means from said actuating means, said control means being responsive to a selected engine condition which is a function of speed, said actuating means having an arm operably connected to said throttle plate, said friction means being engageable with said arm and movable against said arm to increase resistance to arm movement.

3. A dampening device for use with the pivotally mounted secondary throttle plate of an internal combustion engine carburetor comprising actuating means for moving said throttle plate from an open to close position, friction means engageable with said actuating means to dampen the movement thereof, means responsive to a selected engine condition which is a function of speed for engaging said friction means with said actuating means, said actuating means having an arm operably connected to said throttle plate, said friction means' being engageable with said arm and rotatable against said arm to increase resistance to arm movement.

4. A multiple stage carburetor comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, a speed governor for actuating said primary throttle plate, actuating means for moving said secondary throttle plate from an open to close position in said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means comprising a rotatable member having a shaftway formed therein that is non-collinear with the axis of rotation, said arm being inserted in said shaftway, means responsive to an engine governing condition which is a function of speed to rotate said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement.

A multiplestage carburetor comprising primary and secondary throttlebai'rels, a throttleplate being pivotally mounted in each of said barrels, a speed governor for actuating said primary throttle plate, actuating means "re: moving said secondary throttle plate from an open to close .positionin'said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to :said secondary throttle plate, said friction mcanscomprising a-rotatable member having a shaftway formed therein "that-is transverse to the axis of rotation, means responsive to an engine governing condition which isa function of speed to rotate said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement.

6. Amultiple stage carburetor comprising primary and secondary throttlebarrels, a throttle plate being pivotally mounted ineach of said barrels, a speed governor for actuating said primary throttle plate, actuating means for moving said secondarythrottle plate from an open to close position in said barrel, friction means engageable with said actuating means to dampen 'the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means ioomprising'a rotatable member having a shaftway formed therein that is transverse to the axis of rotation, means responsive to-an engine governing condition which is a function of speed to rotate said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement, said responsive means comprising an adjustable spring loaded piston connected to an engine vacuum source, said piston having an eccentric connection with said member to rotate said member on piston movement.

7. A multiple stage carbureter comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, a speed governor for actuating said primary throttle plate, actuating means for moving said secondary throttle plate from open toward closed position, friction means engageable with said actuating means to dampen the movement thereof, speed responsive control means for engaging said friction means with and disengaging said friction means from said actuating means to frictionally retard the movement of said actuating means.

8. A multiple stage carburetor comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, a speed gover nor for actuating said primary throttle plate, actuating means for moving said secondary throttle plate from an open toward closed position in said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means comprising a rotatable member having a shaftway extending therethrough that is non-collinear with the axis of rotation, said arm being inserted in said shaftway, speed responsive control means for rotating said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement after said primary throttle plate has started to close upon the attainment of governed speed, said speed responsive control means comprising a spring loaded piston connected to a manifold vacuum source, said piston having an eccentric connection with said member to rotate said member on piston movement.

9. A multiple stage carburetor comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, a speed governor for actuating said primary throttle plate, actuating means for moving said secondary throttle plate from an open toward closed position in said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means comprising a rotatable member having a shaftway extending therethrough that is non-collinear with the axisof rotation, said arm being inserted in said shaftway, speed responsive control means for rotating said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement after said primary throttle plate has started to close upon the attainment of governed speed, said speed responsive control means comprising a spring loaded piston connected to a governor vacuum source, said piston having an eccentric connection with said member to rotate said member on piston movement.

10. A multiple stage carburetor comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, means for manually controlling the position of said primary throttle plate, actuating means for moving said secondary throttle plate from an open toward closed position in said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means comprising a rotatable member having a shaftway extending therethrough that is noncollinear with the axis of rotation, said arm being inserted in said shaftway, speed responsive control means for rotatingsa'id member so that the walls of said shaftway bear against said arm to increase resistance to arm movement after said primary throttle plate has started to close upon the attainment of governed speed but before said secondary throttle plate starts to close, said speed responsive control means comprising a spring loaded piston connected to a manifold vacuum source, said piston having an eccentric connection with said member to rotate said member on piston movement.

11. A multiple stage carburetor comprising primary and secondary throttle barrels, a throttle plate being pivotally mounted in each of said barrels, means for manually controlling the position of said primary throttle plate, actuating means for moving said secondary throttle plate from an open toward closed position in said barrel, friction means engageable with said actuating means to dampen the movement thereof, said actuating means having an arm operably connected to said secondary throttle plate, said friction means comprising a rotatable member having a shaftway extending therethrough that is noncollinear with the axis of rotation, said arm being inserted in said shaftway, speed responsive control means for rotating said member so that the walls of said shaftway bear against said arm to increase resistance to arm movement after said primary throttle plate has started to close upon the attainment of governed speed, said speed responsive control means comprising a cylinder, a spring loaded piston movable in said cylinder, an eccentric mechanical connection between said piston and said member, said piston being connected to a manifold vacuum source so that after said primary plate has started to close said piston is immediately moved by the manifold vacuum to dampen the secondary throttle plate movement.

12. In an engine having a movable control member, vacuum responsive means for controlling the position of said control member, said vacuum responsive means comprising a chamber having a movable wall and a rod connecting said movable wall to said control member, friction means selectively engageable with said rod to dampen the movement of said control member, and speed responsive control means for engaging said friction means with and disengaging said friction means from said rod.

13. In an engine having a movable control member, actuating means dependent on an engine vacuum condition which is a function of speed for controlling the position of said control member, said actuating means comprising a chamber having a movable wall and a rod connecting said movable wall to said control member, friction means selectively engageable with said rod to dampen the movement of said control member, and control means responsive to a selected engine vacuum condition which is a function of speed for urging said friction means against said rod to increase resistance to the movement of the rod.

14. A multi-stage carburetor for an internal combustion engine, comprising a body with primary and secondary induction passages therethrough and having respectively primary and secondary throttle valves therein controlling the flow of combustible mixtures to said engine, a venturi formed within said primary induction passage, means for manually controlling the position of said primary throttle valve, vacuum responsive means for controlling the position of said secondary throttle valve, said vacuum responsive means comprising a housing having a movable wall therein operatively connected to said secondary throttle valve and adapted to form a chamber, conduit means communicating between a source of venturi vacuum and said chamber, and friction means responsive to variations in engine vacuum for regulating the rate of movement of said wall in response to changes in venturi vacuum in the throttle closing direction.

15. A multi-stage carburetor for an internal combustion engine, comprising a body, primary and secondary induction passages formed through said body, primary 25 and secondary venturis formed respectively within said induction passages, primary and secondary throttle valves located respectively within said induction passages and adapted to control the fiow of combustible mixtures therefrom to the intake manifold of said engine, means for manually controlling the position of said primary throttle valve, vacuum responsive means forcontrolling the position of said secondary throttle, said vacuum responsive means comprising a housing, a movable wall within said housing forming a chamber therein and a rod connecting said movable wall to said secondary throttle valve, conduit means communicating between said chamber and a source of primary venturi vacuum, friction means engageable with said rod to dampen the movement of said secondary throttle valve, and speed responsive control means operatively connected to said friction means for engaging said friction means with and disengaging said friction means from said rod.

16. The carburetor defined in claim 15 wherein said speed responsive control means comprises a spring loaded piston connected to a governor vacuum source.

17. The carburetor defined in claim 15 wherein said speed responsive control means comprises a spring loaded piston connected to a manifold vacuum source.

References Cited in the file of this patent UNITED STATES PATENTS Winkler Sept. 9, 1952 

